Condenser



Deg. 22, 1936. L. G. BURLINGAME 2,064,819

CONDENSER F iled March 30, 1933 INVENTOFI 7; .aa .91 a Les Gfiurhng Patented Dec. 22, 1936 CONDENSER Leslie G. Burlingame, Erlton, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application March 30, 1933, Serial No. 663,433

10 Claims.

The present invention relates to electrical condensers and, more particularly, to electrical condensers having metal foil electrodes and terminal means therefor.

Electrical condensers of the type above referred to usually comprise electrodes of metal foil wound with insulating sheets into a body in the ends of which the marginal edges of the electrodes are presented for connection, at one or more points, with a terminal lead or leads. The terminal means of certain known prior art devices of this character include terminal leads in the form of short lengths of conducting wire, secured mechanically or by fusion, such as by soldering, with the marginal edges of the foil electrodes. Such terminal means are often not sufficiently flexible to withstand repeated flexing in use without breaking away at the joint or tearing out from the foil edges. L

Various expedients have been employed heretofore to overcome the above and other weaknesses in the terminal constructions of foil condensers and like electrical devices, but have not been of practical use because of increased cost, limited flexibility, increased size, lack of adaptability to common forms of apparatus and lack of ability to Withstand ordinary handling in production and use.

It is, accordingly, an objectof my invention to provide an electrical condenser having an improved terminal construction whereby the abovenoted and other disadvantages inherent in known constructions are obviated.

A further object of my invention is to provide animproved condenserhaving a plurality of terminal connections whereby the condenser body may effectively be supported without impairing the union between the condenser and the terminal connections.

A further object of my invention is to provide an improved, flexible terminal construction for electrical foil condensers and the like which provides for easy attachment or removal of the terminal means, thereby facilitating manufacture and repair, and prevents damage to the elements of the device by accidental breakage or removal of the terminal means.

Another object of my invention is to provide improved, flexible terminal members for condensers of the character specified which are attached thereto without the aid of solder.

. A still further object of my invention is to provide an improved electrical condenser of the metal foil type having detachable terminal means providing a relatively large contact area with the electrode elements thereof and means for positively establishing and maintaining an electrical connection between said elements and said terminal means.

With the above and other objects in view, the invention resides in the novel construction, combination, and arrangement of parts, the novel features of which are set forth with particularity in the appended claims. The invention itself, ,however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment, when taken in connection with the accompanying drawing, in which Fig. 1 is an enlarged sectional view of a metal foil condenser and terminal means therefor embodying my invention;

' Fig. 2 is a fragmentary perspective view, on the same scale, of the condenser of Fig. 1, illustrating a step in the assembly operation wherein a terminal member is connected to one end thereof;

Fig. 3 is a similar view illustrating the parts of Fig. 2 in detached, but assembled, relation with respect to one end of the condenser;

Fig. 4 is an end view, on the same scale, of a condenser illustrating a modification of a terminal attaching end plate shown in Figs. 1, 2, and 3;

Fig. 5 is a fragmentary view, in elevation, and also on the same scale, illustrating a modification of a locking bar shown in Figs. 1, 2, and 3; and

Fig. 6 is a view, in elevation and on the same scale, of certain parts in detached, but assembled, relation to each other, illustrating a further modification of my invention.

Referring more particularly to the drawing,

' ments and being spaced edgewise to extend the marginal edge portions 13 thereof beyond the marginal edges of the paper strips II or body of the condenser to provide exposed terminal ends,

for the electrodes.

In accordance with ,my invention, fi condenser I0 is provided at each end with terminal means T which is preferably constituted bya; single length of suitable conducting wire I4 having one of its free end portions convoluted, as indicated at ii, in a plane at right angle to the remaining or terminal lead portion thereof and to a diameter less than the diameter of the free ends of the condenser ID, as clearly shown in Figs. 1, 3, and 4.

The terminal leads H are secured to the ends of the condenser ID, in contacting relation with the exposed convoluted edge [3 of each foil strip l 2, by means of a pair of discs or washers l5 and a locking bar ll. The washers It, preferably of metal and of a diameter substantially equal to the diameter of the free ends of the condenser III, are each provided with a central opening I! having diametrically opposite rectangular recesses or slots I! cut inwardly from the edge defining the opening l8 to form a key-hole. The washers iii are further provided with a plurality of equally spaced minor openings 20 which are suitable length of hard fibre or the like, preferably rectangular incross section, which is provided adjacent each of its free ends 2| with a terminal leads [4 and the washers so assembled,

the locking bar I1 is subsequently inserted in the central opening-23, extending lengthwise through the condenser I0, until the free ends 2i thereofproject an equal distance beyond the ends of the condenser. An assembled terminal lead II and washer l6 are then placed on each of the projecting ends 2| with the convoluted portions I! of each member H in contacting engagement with the respective ends of the condenser Ill.

The condenser N, with the locking bar l1 and the terminal leads l4 and washers I5 as a unit, is now inserted in a suitable press or other pressure exerting means to compress the convoluted portions l5 of the terminal leads l4 into firm contact with the exposed foil edges of the condenser and the washers l6 into alignment with the slots 22 in the locking bar l1.

/ After the washers is have been compressed into alignment with the slots 22, the locking bar i1 is given a quarter turn to cause the slots 22 to lock the washers ii, in theposition to which they have been compressed, by the cooperation of the slots 22 with the diametrically opposite edge portions of the openings It at points removed from the slots is. After the terminal leads ll have been so secured, the condenser is ready to be impregnated ina suitable dielectric com-' pound, the minor openings 20, not occupied by the terminal leads I, assisting the slots I! in permitting ingress of the impregnating compound into the ends of the condenser under the washers i6 and into the central opening 22 occupied by the locking bar I! whereby the said bar is also impregnated.

Among other things, impregnation of the looking bar l'l causes .the said bar to shrink. This is highly desirable since shrinkage of the fibre locking bar l1, after the washers ll have been locked in place thereby, causes the said bar I! to maintain the washers it under constant pressure contact with the convoluted portions ll of the I terminal leads N and the convoluted portions with the ends of the condenser ll.

' In Fig. 4, there is illustrated a modified form of washer 25 having its peripheral edge scalloped to provide a series of circular segments 20 joined at their extremities by a series of radially arranged, inwardly extending slots 21, said slots being adapted to assist the central opening 20 therein and the rectangular slots 2! associated with the opening 28 in permitting ingress of an impregnating dielectric compound into the condenser structure, and also to provide an outlet passage for the free end portion of a terminal lead I similar to the openings 20 shown in connecti with the washer IS in Figs. 2 and 3.

Fig. 5 illustrates one end of a modified form of locking bar ll wherein a portion of the opposite side edges is taperedor undercut, as indicated at ll, to provide shoulders 22 adapted for cooperative locking engagement with either form of washer illustrated, in a manner similar to that hereinbefore described. From a consideration oi the above, it will readily be apparent that, in the attachment of the terminal leads H to the condenser I! by means of the washers I and a locking bar, as exemplified in Fig. 5, the application of pressure to the washers It need not be so regulated as to insure the exact alignment of the washers I i with the rectangular slots 22, since the absence of shoulders opposite tothe shoulders 32, shown in Fig. 5, obviates the necessity for exact alignment and thereby facilitates the sttachment of the terminal leads I to the condenser l0.

While I have described the locking bar I! asv being formed preferably of hard fibre or the like, and the washers It as of metal, it is to be expressly understood that I consider it within the scope of my invention to employ a metallic locking bar and a washer of bakelite or other form.

annular flange 25 projecting centrally from one,

side thereof,-is preferably interposed between the metallic spring washer. 32 and the convoluted portion is of the terminal leads I with the annular flange of the said additional washer projecting into the central opening 23 in the condenser It to insulate the end portion of the metallic locking bar from the convoluted marginal edge of the foil layers, adjacent the axial center of the condenser.

Also, as shown in Fig. 6, in lieu of the form of locking bar shown in Figs. 1, 2, 3, and 5, I may utilize a metallic bar 36, either rectangular or cylindrical, solid or tubular in cross section, having a slot 31 cut inwardly axially of its free ends,

to divide each free end portion of the bar whereby a terminal lead II, the intermediate flanged fibre washer 24, andthe dished spring washer 83 may all be attached'to each end of the condenser II by separating the divided end portions 21 of the barwover the outer surface of the spring washer.

manner herein set forth, the condenser I0 is preferably inserted in a tubular container 38 (Fig. 1) of suitable insulating material or, alternatively, in a wrapper of similar material. The container or wrapper is preferably of a length substantially greater than the length of the condenser ID to provide an opening 39 at each end of the condenser adapted for the reception of a suitable sealing compound as indicated at 40,

whereby the said condenser, with the attached ends of the terminal members I4, is efiectively sealed within the container.

I claim as my invention:

1. In a fixed condenser having marginal foil edges projecting from each end thereof and a central opening extending throughout its length, a pair of flexible terminal members each having an end portion thereof contacting one of said foil edges, clamping elements for said terminal members, provided, each, with an aperture in the form of a key-hole, a locking bar extending through said central opening and the aperture of each clamping element, and a key carried by the end portions of said bar for locking each of said apertured elements to its associated terminalmember upon partial rotation of said locking bar whereby said terminal members are secured in abutting relation to theterminal means of said condenser.

2. In a fixed condenser of the rolled foil type having an axial opening throughout its length and presenting exposed foil-edges at the ends thereof, a terminal member for each foil edge, the said members each having a free end and an end angularly disposed thereto, the angularly disposed end of one member being in contacting engagement with one foil edge and the angularly disposed end of the other member being in contacting engagement with the remaining foil edge, a pair of locks each constituted by a multi-perforated disc associated, respectively, with the angularly disposed ends of the several terminal members and through each of which the free end of the respectively associated terminal member extends, a clamping member having oppositely located key-shaped ends extending through said axial opening and through said discs, the ends of the clamping member and the perforations in the discs which accommodate them having such con- I figuration that rotation of the said member with respect to the said discs gives rise to a locking action, a containerior said condenser, and means for sealing said condenser'within said container.

3. The combination with an electrical condenser having a spiral electrode and an insulating body in which an edge of said electrode is exposedas a terminal element therefor, of a flexible terminal member for said electrode comprising a convoluted wire portion arranged to lie in contact with the edge of said electrode, said convoluted portion having a terminal lead extending therefrom, a disc for engaging and holding said convoluted wire portion in direct contact with saidexposed electrode edge, said disc having an orifice therein to accommodate said terminal lead and a second orifice in the form of a key-hole,

. a locking bar having a key portion extending bedenser whereby said bar and disc frictionally and conductlvely engage said flexible terminal member with the edge of said spiral electrode.

4. In a condenser presenting an exposed marginal foil edge lying in the end of the body thereof, a terminal member adapted to contact said foil edge, a disc for clamping said terminal member against said foil edge, said disc having a slot therein, a locking bar extending through the body of said condenser and having a recessed end adapted to be passed through said slot in said disc and, by relative movement of said rod and disc adapted to lock said terminal member against said foil edge.

5. The invention as set forth in claim 4 further characterized in this, that said locking bar is composed of fibrous material treated to ensure shrinkage whereby it exerts continuous pressure against said clamping disc.

6. In an electrical device having an opening therethrough, terminal members contacting said device, a clamping rod extending through said opening and engaging said terminal members, said clamping rod having a permanent shrinkage factor whereby said terminal members are maintained under pressure contact with said device.

7. In an impregnated electrical device having a central opening throughout its length, terminal members contacting the ends of said device, an impregnated clamping rod extending through said central opening and engaging said terminal members, said clamping rod having a permanent shrinkage factor whereby said terminal members are maintained under continuous pressure'contact with said ends of said device.

8. The invention as set forth in claim '7 further characterized in this, that said terminal members are orificed to permit impregnation of the interior of said condenser after assembly.

9. In a condenser having a plurality of metallic foils separated by insulating material and rolled into substantially cylindrical form with one marginal foil edge projecting from each end of said condenser, a pair of terminal members adapted to be secured in abutting relation with the projecting marginal foil edges and each having a terminal lead extending from one end thereof, a disc cooperatively associated with each terminal member, said discs each having an orifice to accommodate said terminal leads, and a rod of impregnated fibre having a permanent shrinkage factor extending axially of said condenser and connecting said discs for maintaining said terminal members in contacting relation with the projecting foil edges of said condensers.

10. The combination with an impregnated electrical apparatus having a body portion and electrode terminals at each end, a detachable terminal means therefor comprising a convoluted terminal member engaging said electrode terminals, said members each having'a terminal lead extending from one end thereof, and clamping means extending in partthrough said bodyportion and mechanically connecting said convoluted terminal members, the part of said clamping means extending through said body portion being composed of impregnated fibre and having a permanent shrinkage factor whereby said convoluted terminal members are maintained under constant pressure with said electrode terminals.

. LESLIE G. BURLINGAME. 

